Technical Abstract:
Brazil is one of the largest producers of animal protein in the world. Productions are concentrated in certain regions of the country. Intensification of animal production may provide constant threat to the quantity and quality of water resources. The objective of this study was to evaluate the impact of livestock on water quality of Pinhal River sub-basin. This sub-basin is located in Concordia, West part of Santa Catarina State. Eight sampling sites representing different land-uses (LU1- dairy cattle; LU2- without animals; LU3- dairy + pigs + poultry + crops; LU4– pigs + poultry + crops; LU5– dairy + pigs + poultry + crops + human; LU6 – dairy + pigs + crops; LU7 and LU8- dairy + pigs) along the Pinhal River were sampled from 2006 to 2009. LU1 had the worst water quality having the highest concentrations of TSS, COD, TP, Fecal coliforms and E. coli because cows had direct access to the river. The highest concentration of nitrate was found at the mouth of the river. There were higher concentrations of TSS, DO, N-NO2 and NO3-N in wet season when compared with their summer averages. At this time, there was intensive fertilizer application to growing corn. Autumn and winter presented the worst water quality because of high nitrogen, phosphorus and coliforms. During spring and summer, presence of Salmonella was considerably high. Our results confirmed the relationship between the type of pollution sources (i.e., cows, pigs and poultries) and water quality. Properly managed animal, right amount of and correct timing of fertilizers application along with functioning riparian zone may improve water quality.